Knob for radio control shafts



April 10, 1934. J WALTER 1,954,062

KNOB FOR RADIO CONTROL SHAFTS Filed Feb. 20, 1932 $1 512 F1415. Fza:

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Patented Apr. 10, 1934 UNITED STATES PATENT OFFICE 9 Claims.

The present invention relates to knobs for radio control shafts, and has for its object the provision of a control knob, which is easily mounted and demounted on its shaft, is positive in its gripping action on the shaft due to various features which will be described in detail in the following specification.

The knob in hand has also certain manufacturing advantages which permit of its being readilyv made in large numbers, as will be explained herein.

The body of the present knob is formed from semi-plastic fibrous material, which when hardened forms a positive grip around the end of the control shaft, as will also be explained hereinafter as the description proceeds.

In the accompanying drawing forming part of the present specification, I have illustrated the invention constructed according to the best mode I have so far devised for the application of the principles.

Figure 1 is a vertical section through the fibre knob, showing same mounted on a radio control shaft.

Figure 2 is a top plan view of the metal insert shown in Figure 1.

Figure 3 is a side view of the said metal insert taken from the left thereof as seen in Figure 1.

Figure 4 is a side view of said insert taken from the right as seen in Figure 1.

Figure 5 is a bottom plan view of the metal insert shown in Figure 1.

Figure 6 is a bottom view of the knob shown in Fig. 1.

* Figure 7 is a top plan view of modified insert it used.

Figure 8 is a side view of Figure 7. Figure 9 is a right side view of Figure 8. Figure 10 is a bottom view of a modified type of knob.

Referring to thedrawing, the numeral 1 indicates a-fibre knob which is mounted on the end of the radio control shaft 2, the latter being formed as shown in Figures 1 and 6 with an outwardly extending end 3, one side 4 of which is made fiat and has a notch 5, which is cut at substantially right angles to the surface of the shaft, and has a bevelled side 6 therein. The extension 3 has a bevelled edge 7, the purpose of which will be explained below. The fibre knob l is provided with a recess 9. and a second recess 10, for the purpose of admitting into the knob the extension 3 of the radio control shaft 2. Within the fibre knob 1 is also positioned a metal spring plate 11 of substantially U-form, as illustrated in Figure 1 and provided with the two outstanding cars 12 and 13, to provide a rigid mounting of the plate 11 in the knob material. The ears 12 and 13 are preferably cut from the material of the plate 11, as shown in Figures 3 and 4 and bent outwardly into position, as shown in Figures 1 and 2 clearly.

It will be noted that while in Figure 2, the said ears 12 and 13 are shown rectangular in outline that any other convenient shape such as a semicircular one (not shown), may be used therefor. At 14 is shown an outwardly turned flange, as shown in Figures 1 and 3 of the drawing, for the same purpose of embedding the spring-plate 11 rigidly in the fibre knob when the fibrous material composing same is properly hardened, as will be explained hereinafter. It is seen from Figure 1 that when the knob 1 is mounted on the control shaft 2 that the curved and bent end 15 of said plate 11 elastically engages the bevel 6 of the recess 5, the portion 16 of the plate being fulcrumed about the point 17 at the upper edge of the recess 9. It is seen that the amount of spring tension in the portion 16 of the plate 11 depends on the depth of the recess 9 from the bottom surface 20 of the knob 1, and consequently any particular desired amount of tension in said portion 16, can be obtained by merely reducing or increasing the depth of the cavity 9 when the knob is be ing formed, as is at once understood.

The bevelled edge 7 on the extension 3 of the radio shaft is to insure a good contact between the square upper end 18 of said extension, and the transverse portion 21 of the spring-plate 11. On the bottom end 20 of the knob 1, is formed a concavity 22, so that when the knob 1 is mounted on the shaft 2, the peripheral edge 23 of the knob 1 will be parallel to the face of the radio cabinet, and prevent any great amount of frictional adherence of the face of the knob against the 95 cabinet.

There are certain advantages which the present type of knob possesses with reference to its manufacture in large numbers, which it is not necessary to explain in the present specification, as they 100 relate more to the manufacture of the knob than to the knob itself, as an article of manufacture.

From what has been said above, it will be seen that when the radio knob is mounted on the end of the shaft 2, the knob can be readily slid on to the shaft 2, and the resilient end 16 of the springplate 11 will readily slide along the surface 4 of the shaft, and snap into the recess 5, and lockingly engage the bevelled surface 6 of said recess. As the material of the knob closely surrounds the peripheral edge 24 of the shaft 2, the upper end 18 of the shaft fits perfectly against the transverse portion'21 of the spring-plate 11, and the bent end 15 lockingly engages the bevel 6 of the recess 5 the knob 1 is securely held in rigid position on the shaft 2. In mounting the knob 1 on the shaft 2, a definite click is heard as the bent end 15 snaps into the recess 5 of the shaft, clearly indicating when the knob has reached its seat and is perfectly mounted. This is an advantageous feature in assembling the knobs on the radio shafts. Moreover, it is evident that due to the resilient engagement of the bent end 15 in the recess 5, the knob can be removed from the shaft and readily replaced when necessary.

Attention has been called above to the fact that the amount of tension in the portion 16 of the spring-plate 11 can be adjusted to the proper amount, when the knob is being formed by using the proper depth of recess 9, and this is considered an important feature of the invention. The knob is made of semi-plastic fibrous material and a mandrel of shape corresponding to the extension 3 of the shaft 2 is used during its manufacture, and the mandrel with a spring-plate 11 thereon inserted in the semi-soft fibrous material of which the knob is made, thereby insuring a perfect mounting of the metal spring-plate 11 in the material of the knob; and the fibrous material completely surrounds the peripheral edge of the extension 3, so that the recess 10 forms a perfect fit around said extension 3 of the shaft 2. In this way, all play between the end of the radio shaft and the knob is eliminated and a perfect grip is obtained by the knob on the end of the radio control shaft.

In the Figures 7, 8 and 9 of the drawing, is

. illustrated a modified form of a metal insert which may be used in lieu of the one previously described herein. In these figures, 24 indicates a metal U-shaped spring-plate insert which is provided with one leg 25 of greater width than the oppositely disposed leg 26, for the purpose of permitting the portion 26 to move freely in the recess 9.

It will be noted that the modified form of insert has two outwardly extending ears 27, 28 which correspond to the ear 13 in the form of the device shown in Figures 1 and 2 of the drawing. As these inserts are both embedded in the material of the knob 1, it may be found preferable for purposes of manufacture to omit the flange 14 and the ear 12 shown in Figure 1, in which event the insert takes practically the form shown in the Figures '7 to 9 inclusive.

Figure 10 shows a bottom view of a knob having the type of insert shown in Figure 9 inserted therein. It is seen in this view the auxiliary recess 29 takes a sectorial shape in cross-section, which is a convenient shape for manufacturing purposes, and as the leg 26 of the insert 24 is narrower than the diametrical size of said recess, said leg can be freely operated in the auxiliary recess.

I claim:

1. In a radio control-shaft knob, a U-shaped bar-like member, an outwardly bent flange on one end of said member, a resilient portion on the other end of same, and a pair of opposed outwardly extending prongs formed near the closed transverse portion of the U-shaped member.

2. Aknob adapted to be mounted on the notched partially cylindrical and partially fiat sided end of a radio control-shaft, comprising a body of fibrous material, having a recess therein formed complementary to the end of the control-shaft, and having a second and adjacent recess in said body, a U-shaped bar-like member rigidly mounted in the first-named recess, a resilient end on the U-shaped member operating in the secondnamed recess, and adapted to engage the notched end of the control-shaft for positively securing the knob on said shaft.

3. In a radio control-shaft knob, a knob body having a recess of partially cylindrical and partially flat sided cross-sectional outline, and an adjacent recess to the first-named recess, a fulcrum-like shoulder formed in the body material of said knob at a point where the two recesses adjoin each other, a U-shaped member rigidly mounted in the first-named recess, a resilient portion on the U-shaped member in engagement with the knob material adjacent to the said fulcrumlike shoulder, and the lower end of said resilient portion being adapted to lockingly engage the end of the control-shaft for the purpose of securing the knob on said shaft.

4. In a radio control-shaft knob, a U-shaped bar-like member, a resilient leg portion having a convex extremity thereon, formed on one end of the U-shaped member, and an oppositely disposed leg portion of greater width than the firstnamed leg portion, formed on the other end of the U-shaped member, and a pair of outwardly extending integral prongs formed near the transverse portion of said member.

5. In a radio control-shaft knob, a knob body having a recess of partially cylindrical and partially fiat-sided cross-sectional outline, and an adjacent auxiliary recess therein, a fulcrum-like shoulder formed in the body material of said knob at a point where the two recesses adjoin each other, a U-shaped member rigidly mounted in the first-named recess, a resilient depending leg on the U-shaped member having a convex end operating within the auxiliary recess, and adapted to lockingly engage on the control-shaft, and a second depending leg on the U-shaped member rigidly mounted in the material of the knob, and of greater width than the first-named leg.

6. In combination, a cylindrical radio controlshaft, having a cut-away portion with a bevelled notch formed therein, a knob of fibrous material having a complementary recess therein adapted to receive the endof the control-shaft, a U- shap'ed member having 2. depending portion thereon rigidly mounted in the knob material, a resilient portion on the other end of the U-shaped member, of less width than the said depending portion thereof, and having a curved end adapted to lockingly engage the bevelled notch of the control-shaft.

7. In a radio control-shaft knob, a knob body having a recess of partially cylindrical and partially flat-sided cross-sectional outline, and an adjacent auxiliary recess of sectorial shape therein, a fulcrum-like shoulder formed in the body material of said knob at a point where the two recesses adjoin each other, a U-shaped member rigidly mounted in the first-named recess, a resilient depending leg on the U-shaped member having a convex end operating within the auxiliary recess, and adapted to lockingly engage on the control-shaft, and a second depending leg on the U-shaped member rigidly mounted in the material of the knob, and of greater width than the first-named leg.

8. In combination, a radio control-shaft, having a cut-away portion with a beveled notch formed therein, a knob having a complementary recess therein adapted to receive the end of the control-shaft, a U-shaped member rigidly mounted in the knob recess, a. pair of opposed outwardly extending prongs on the U-shaped member formed adjacent the closed transverse portion of same, and embedded in the knob, for holding the U-shaped member in position, and a resilient portion on the end of the U-shaped member, adapted to loekingly engaged the notch of the control-shaft.

9. A radio control-shaft knob, having a major recess therein formed complementary to the end of the control-shaft, and having an auxiliary recess therein, adjacent to the first-named recess,

a U -shaped member mounted in the knob, a resilient leg portion on the end of the U-shaped member, of a width adapted to permit tree move-- ment of same within the auxiliary recess, a pair of opposed outwardly extending ears on the transverse portion of the U-shaped member, and embedded in the knob material, for holding the U-shaped member in said knob, and a second leg portion on the U-shaped member, of greater width than the said resilient leg portion of same, rigidly embedded in the knob material, for holding the U-shaped member in position in the knob.

JOHN WALTER. 

